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Article Reference Sonotype-level responses of Afrotropical hipposiderid bats to local-scale effects of rainforest structure
Located in Library / RBINS Staff Publications 2023 OA
Article Reference The Macquenoise sandstone (Devonian – Lochkovian), a suitable raw material for ancient querns and millstones: quarries, properties, manufacture and distribution in France and Belgium
ABSTRACT. For some years, a French-Belgian team of archaeologists and geologists is investigating the provenance of ancient quern-stones and millstones. Their study revealed the frequent occurrence of particular coarse sandstones derived from Lower Devonian strata in the Ardenne region, known as either the “Arkose of Haybes” by geologists or the “Arkose of Macquenoise” by archaeologists. Material for Late Iron Age and Roman quern-stones and millstones was quarried from open pits located west of the border between France and Belgium, between the Belgian village of Macquenoise (Commune of Momignies, Province of Hainaut) and the French town of Hirson (Aisne Department, Hauts-de-France region). This paper describes the raw materials, presents the different types of grindstones produced through historical times and provides a detailed diffusion map of the millstones. KEYWORDS: arkose, Lochkovian, milling stone, Gallo-Roman quarry, distribution area, geoheritage.
Located in Library / RBINS Staff Publications 2018
Article Reference Assessment of PRISMA water reflectance using autonomous hyperspectral radiometry
Hyperspectral remote sensing reflectance (Rrs) derived from PRISMA in the visible and infrared range was evaluated for two inland and coastal water sites using above-water in situ reflectance measurements from autonomous hyper- and multispectral radiometer systems. We compared the Level 2D (L2D) surface reflectance, a standard product distributed by the Italian Space Agency (ASI), as well as outputs from ACOLITE/DSF, now adapted for processing of PRISMA imagery. Near-coincident Sentinel-3 OLCI (S3/OLCI) observations were also compared as it is a frequent data source for inland and coastal water remote sensing applications, with a strong calibration and validation record. In situ measurements from two optically diverse sites in Italy, equipped with fixed autonomous hyperspectral radiometer systems, were used: the REmote Sensing for Trasimeno lake Observatory (RESTO), positioned in a shallow and turbid lake in Central Italy, and the Acqua Alta Oceanographic Tower (AAOT), located 15 km offshore from the lagoon of Venice in the Adriatic Sea, which is characterised by clear to moderately turbid waters. 20 PRISMA images were available for the match-up analysis across both sites. Good performance of L2D was found for RESTO, with the lowest relative (Mean Absolute Percentage Difference, MAPD  25\%) and absolute errors (Bias  0.002) in the bands between 500 and 680 nm, with similar performance for ACOLITE. The lowest median and interquartile ranges of spectral angle (SA  8°) denoted a more similar shape to the RESTO in situ data, indicating pigment absorption retrievals should be possible. ACOLITE showed better statistical performance at AAOT compared to L2D, providing R2  0.5, Bias  0.0015 and MAPD  35\%, in the range between 470 and 580 nm, i.e. in the spectral range with highest reflectances. The addition of a SWIR based sun-glint correction to the default atmospheric correction implemented in ACOLITE further improved performance at AAOT, with lower uncertainties and closer spectral similarity to the in situ measurements, suggesting that ACOLITE with glint correction was able to best reproduce the spectral shape of in situ data at AAOT. We found good results for PRISMA Rrs retrieval in our study sites, and hence demonstrated the use of PRISMA for aquatic ecosystem mapping. Further studies are needed to analyse performance in other water bodies, over a wider range of optical properties.
Located in Library / RBINS Staff Publications 2022
Article Reference QWIP: A Quantitative Metric for Quality Control of Aquatic Reflectance Spectral Shape Using the Apparent Visible Wavelength
The colors of the ocean and inland waters span clear blue to turbid brown, and the corresponding spectral shapes of the water-leaving signal are diverse depending on the various types and concentrations of phytoplankton, sediment, detritus and colored dissolved organic matter. Here we present a simple metric developed from a global dataset spanning blue, green and brown water types to assess the quality of a measured or derived aquatic spectrum. The Quality Water Index Polynomial (QWIP) is founded on the Apparent Visible Wavelength (AVW), a one-dimensional geophysical metric of color that is inherently correlated to spectral shape calculated as a weighted harmonic mean across visible wavelengths. The QWIP represents a polynomial relationship between the hyperspectral AVW and a Normalized Difference Index (NDI) using red and green wavelengths. The QWIP score represents the difference between a spectrum’s AVW and NDI and the QWIP polynomial. The approach is tested extensively with both raw and quality controlled field data to identify spectra that fall outside the general trends observed in aquatic optics. For example, QWIP scores less than or greater than 0.2 would fail an initial screening and be subject to additional quality control. Common outliers tend to have spectral features related to: 1) incorrect removal of surface reflected skylight or 2) optically shallow water. The approach was applied to hyperspectral imagery from the Hyperspectral Imager for the Coastal Ocean (HICO), as well as to multispectral imagery from the Visual Infrared Imaging Radiometer Suite (VIIRS) using sensor-specific extrapolations to approximate AVW. This simple approach can be rapidly implemented in ocean color processing chains to provide a level of uncertainty about a measured or retrieved spectrum and flag questionable or unusual spectra for further analysis.
Located in Library / RBINS Staff Publications 2022
Article Reference Pierres à aiguiser de l'habitat rural médiéval au "Grand Fauvage" (Marche-en-Famenne, Province du Luxembourg, Belgique)
Located in Library / RBINS Staff Publications 2023
Inbook Reference Classification of Multibeam Sonar Image Using the Weyl Transform
Located in Library / RBINS Staff Publications 2020
Article Reference 33 million year old Myotis (Chiroptera, Vespertilionidae) and the rapid global radiation of modern bats
The bat genus Myotis is represented by 120+ living species and 40+ extinct species and is found on every continent except Antarctica. The time of divergence of Myotis has been contentious as has the time and place of origin of its encompassing group the Vespertilionidae, the most diverse (450+ species) and widely distributed extant bat family. Fossil Myotis species are common, especially in Europe, beginning in the Miocene but earlier records are poor. Recent study of new specimens from the Belgian early Oligocene locality of Boutersem reveals the presence of a relatively large vespertilionid. Morphological comparison and phylogenetic analysis confirms that the new, large form can be confidently assigned to the genus Myotis, making this record the earliest known for that taxon and extending the temporal range of this extant genus to over 33 million years. This suggests that previously published molecular divergence dates for crown myotines (Myotis) are too young by at least 7 million years. Additionally, examination of first fossil appearance data of 1,011 extant placental mammal genera indicates that only 13 first occurred in the middle to late Paleogene (48 to 33 million years ago) and of these, six represent bats, including Myotis. Paleogene members of both major suborders of Chiroptera (Yangochiroptera and Yinpterochiroptera) include extant genera indicating early establishment of successful and long-term adaptive strategies as bats underwent an explosive radiation near the beginning of the Early Eocene Climatic Optimum in the Old World. A second bat adaptive radiation in the New World began coincident with the Mid-Miocene Climatic Optimum.
Located in Library / RBINS Staff Publications 2017
Article Reference Estimating body size in early primates: The case of Archicebus and Teilhardina
Obtaining accurate estimations of the body mass of fossil primates has always been a subject of interest in paleoanthropology because mass is an important determinant for so many other aspects of biology, ecology, and life history. This paper focuses on the issues involved in attempting to reconstruct the mass of two early Eocene haplorhine primates, Teilhardina and Archicebus, which pose particular problems due to their small size and temporal and phylogenetic distance from extant primates. In addition to a ranking of variables from more to less useful, the effect of using models of varying taxonomic and size compositions is examined. Phylogenetic correction is also applied to the primate database. Our results indicate that the choice of variable is more critical than the choice of model. The more reliable variables are the mediolateral breadth across the femoral condyles and the area of the calcaneocuboid facet of the calcaneus. These variables suggest a body mass of 39 g (range 33e46 g) for Archicebus and 48 g (range 44 e56 g) for Teilhardina. The width of the distal femur is found to be the most consistent estimator across models of various composition and techniques. The effect of phylogenetic correction is small but the choice of branch length assumption affects point estimates for the fossils. The majority of variables and models predict the body mass of Archicebus and Teilhardina to be in the range of the smaller extant mouse lemurs, as expected.
Located in Library / RBINS Staff Publications 2017
Article Reference Changes in chlorophyll concentration and phenology in the North Sea in relation to de‐eutrophication and sea surface warming
At least two major drivers of phytoplankton production have changed in recent decades in the North Sea: sea surface temperature (SST) has increased by ~ 1.6°C between 1988 and 2014, and the nitrogen and phosphorus loads from surrounding rivers have decreased from the mid‐1980s onward, following reduction policies. Long time series spanning four decades (1975–2015) of nutrients, chlorophyll (Chl), and pH measurements in the Southern and Central North Sea were analyzed to assess the impact of both the warming and the de‐eutrophication trends on Chl. The de‐eutrophication process, detectable in the reduction of nutrient river loads to the sea, caused a decrease of nutrient concentrations in coastal waters under riverine influence. A decline in annual mean Chl was observed at 11 out of 18 sampling sites (coastal and offshore) in the period 1988–2016. Also, a shift in Chl phenology was observed around 2000, with spring bloom formation occurring earlier in the year. A long time series of pH in the Southern North Sea showed an increase until the mid‐1980s followed by a rapid decrease, suggesting changes in phytoplankton production that would support the observed changes in Chl. Linear correlations, however, did not reveal significant relationships between Chl variability and winter nutrients or SST at the sampling sites. We propose that the observed changes in Chl (annual or seasonal) around 2000 are a response of phytoplankton dynamics to multiple stressors, directly or indirectly influenced by de‐eutrophication and climate warming.
Located in Library / RBINS Staff Publications 2019
Article Reference Salinity predicts the distribution of chlorophyll a spring peak in the southern North Sea continental waters
In the North Sea, the coastal waters of Belgium and The Netherlands regularly exhibit intense spring phytoplankton blooms where species such as Phaeocystis recurrently form a potential ecological nuisance. In the Belgian and Dutch continental shelves (BCS and DCS), we observe a direct correlation between the chlorophyll a spring maximum (Chlmax) and the nutrients (DIN and DIP) available for the bloom. As the nutrients are themselves strongly correlated with salinity, a rationale is developed to predict Chlmax from winter salinity. The proposed rationale is first tested in a theoretical case with a 3D-biogeochemical model (3D-MIRO&CO). The method is then applied to independent sets of in situ observations over 20 years in the BCS and the DCS, and to continuous FerryBox data in April 2008. Linear regressions explain the relationships between winter nutrients and winter salinity (R2 = 0.88 to 0.97 with model results, and R2 = 0.83 to 0.96 with in situ data). The relationship between Chlmax and the available nutrients across the salinity gradient is also explained by yearly linear regressions (R2 = 0.82 to 0.94 with model results, and R2 = 0.46 to 0.98 with in situ data). Empirical ‘DIP requirement’ and ‘DIN requirement’ for the spring biomass bloom formation are derived from the latter relationships. They depend i.a. on the losses from phytoplankton during the spring bloom formation, and therefore show some interannual variability (8–12% for DIP and 13–20% for DIN). The ratio between nutrient requirements allows predicting in winter which nutrient will eventually limit the spring biomass bloom along the salinity gradient. DIP will generally be limiting in the coastal zone, whereas DIN will generally be limiting offshore, the switch occurring typically at salinity 33.5 in the BCS and 33.6 in the DCS. N reduction should be prioritized to limit Phaeocystis in the coastal zone, with target winter DIN:DIP ratios below 34.4 molN molP−1 in the BCS, or 28.6 molN molP− 1 in the DCS.
Located in Library / RBINS Staff Publications 2019